With a recent tendency toward miniaturization of interconnects and multilevel metallization in a semiconductor integrated circuit device, a so-called damascene technique for use in the formation of interconnects or the like, by forming a trench in an insulating film and then embedding a conductive film inside of the trench, has been under investigation.
This damascene technique includes a single damascene method of embedding a trench for an interconnect and a trench for connecting between interconnects by two different steps and a dual damascene method of simultaneously embedding these two trenches. As a conductive film to be embedded in these trenches, a copper film or the like having a small electrical resistance is used.
Inside of the trench, a conductive film having a barrier property (which will hereinafter be called a “barrier film”) is formed in order to prevent diffusion of a metal into an insulating film, such as the copper constituting the conductive film to be embedded, or in order to improve the adhesion between the conductive film to be embedded and the insulating film.
For instance, in NIKKEI MICRODEVICES, PP 65 to 66 (July, 2000), it is pointed out as a problem that, upon formation of an underlying film on the inside wall of a hole by sputtering, sputter particles move easily at the peripheral part of a wafer, thereby deteriorating the ability to uniformly cover the holes.